The Siemens SENTRON 5SY7650-7 is a 4-pole miniature circuit breaker (3P+N) with a C tripping characteristic, rated 50 A at 35 °C and 400 V AC.
The 50 A rating is at 35 °C ambient. In a warm cabinet — say 45 °C — the breaker must be derated to 47 A; at 50 °C it drops to 45.95 A, and at 60 °C to 43.8 A. If your panel runs hot, size the load below these derated figures or the breaker may nuisance-trip. The 15 kA (EN 60898) / 20 kA (IEC 60947-2) breaking capacity tells you the maximum fault current it can interrupt at 400 V AC — enough for most industrial sub-distribution boards with a transformer upstream.
Mounting position is any — no orientation restrictions. Touch protection is built in (IP20 with connected conductors).